Lopez, 38, is best known as the host of TV's "Extra" entertainment news program. He also was a cast member of the 1990s sitcom "Saved by the Bell."
Mazza, 28, is a dancer, who has appeared in the Broadway musicals "A Chorus Line" and "The Little Mermaid."
The couple are the parents of a 2-year-old daughter.
"We took a walk alone as the sun was setting," Lopez told UsMagazine.com of how he proposed to his girlfriend and how she accepted. "I told Courtney that I wanted the mother of my children to have their last name. She was silent at first from shock, then she leaped for joy and did a little jete."
"Besides our daughter's birth, this was the best moment of my life!" Mazza added.
Lopez and Mazza told the magazine they plan to marry in Mexico this year.